Method of preparing lumber having properties of clear grade lumber from common grade lumber

ABSTRACT

Clear grade construction lumber meeting American Lumber Standard size dimensions is prepared by cutting standard dimension common grade lumber having a thickness of 1 1/2 inches along a plane equi-distant between its faces, finishing each of the resultant pieces to a thickness of 5/8 inch and laminating 1/8 inch hardboard to one surface thereof.

United States Patent 1 91 1111 3,865,681 Beebe 1 1 Feb. 11, 1975 [5 METHOD OF PREPARING LUMBER 2,158,908 5/1939 Ottinger 161/268 x HAVING PROPERTIES OF CLEAR GRADE g g Q men 01' LUMBER FROM COMMON GRADE 3,573,145 3/1971 Witkosky et al 161/41 LUMBER 3,741,853 6/1973 Forsythe et al. .1 161/41 Primary ExaminerPhilip Dier Attorney, Agent, or FirmWilliam .1. Mason [57] ABSTRACT Clear grade construction lumber meeting American Lumber Standard size dimensions is prepared by cutting standard dimension common grade lumber having a thickness of l /2 inches along a plane equi-distant between its faces, finishing each of the resultant pieces to a thickness of inch and laminating Vs inch hardboard to one surface thereof.

4 Claims, 5 Drawing Figures PMENTED 3,865,681

(STEP I) (STEP 2) (STEP 3) (STEP 4) METHOD OF PREPARING LUMBER HAVING PROPERTIES OF CLEAR GRADE LUMBER FROM COMMON GRADE LUMBER BACKGROUND OF THE INVENTION Lumber used in the building trades is classified as either clear grade or common grade. Clear grade lumber is characterized by being substantially free of defects such as knots and checks and is A the visible or exterior of structures and finds such end uses as exterior trim, siding, cornices, door jambs, suffits, and the like.

Use of common grade lumber, because of the presence of defects, is confined to applications where appearance is not a factor. Accordingly, common grade lumber is used primarily as joists, studs, and other members of the interior frame structure.

It is the usual practice in the lumber industry to describe construction lumber as being of 1 inch and 2 inches in thickness. In actuality, such lumber is 182 inch and l /zinches thick, respectively. Similarly, width designations of 2, 3, 4, 5, 6, 8, and 12 inches actually describe lumber which is 1% inch less in width, e.g., a 4 inch thickness is actually a 3V2 inch thickness.

The building and lumber trades would be benefited, and lumber could be used more economically and with greater efficiency, if common grade lumber heretofore useful primarily only in non-visible application could be used in exterior or visible applications now restricted to clear grade lumber.

OBJECTS OF THE INVENTION It is an object of the present invention to provide lumber for the building trade which is prepared from standard dimension common grade lumber and which meets the requirements for clear grade lumber.

Another object of the present invention is to provide a process for preparing lumber having the properties of clear grade lumber from common grade lumber of standard commercial dimensions.

Other objects, if not specifically set forth herein, will be obvious to the skilled artisan from reading the detailed description of the invention which follows, particularly with reference to the drawing.

DRAWING The drawing appended hereto serves to illustrate the steps comprising the present invention, including the optional step of adding a backing material, and the product produced thereby.

Specifically in the drawing:

Step 1 illustrates a commercially available lumber piece having a thickness of 1 /2 inches;

Step 2 illustrates the common grade lumber piece after it has been cut into two pieces, each having a thickness of 11/16 inch, a /8 inch section having been removed equidistant between the faces of the lumber pieces;

Step 3 illustrates the two lumber pieces of Step 2 after they have been planed to a thickness of /2 inch;

Step 4 illustrates the two lumber pieces after a hardboard surface having a thickness of As inch has been laminated to one surface of each piece; and

Step 5 illustrates the two lumber pieces additionally having a conventional backing material laminated to the opposite side of each piece.

DETAILED DESCRIPTION In preparing products of the present invention, a standard, commercially available lumber piece (see step 1), having a thickness of 1 /2 inches is cut along a plane equi-distant between its two faces to produce two pieces each having a thickness of 1 1/16 inch, the cutting blade removing a inch section of lumber, i.e., a A; kerf (see step 2). Each of these pieces is thenplaned 0 on the cut surface to a depth of H16 inch to produce a piece having a thickness of We inch (see step 3). A hardboard surface H having a thickness of 4; inch is then laminated to one surface of each piece to produce a product having a thickness of% inch (see step 4). Although the hardboard shown in the drawing has a smooth surface it will be apparent that hardboard having a textured, e.g., wood grain, surface can be used. Various conventional adhesives such as water-base contact adhesives, may be used to laminate the hardboard to the common lumber.

It is noted that adhesive lamination as a means for securing together two wood pieces is well recognized in the prior art, for example, see U.S. Pat. Nos. 2,158,908 and 3,741,853. It is also noted that plywood is commonly formed by adhesively laminating a plurality of wood sheets in face-to-face relationship.

If desired, voids such as knot holes and cracks visible on the side of the lumber opposite the hardboard may be filled with wood filler or putty and sanded level with the lumber.

Optionally, a sheet of Kraft paper or other conventional backing material B may be laminated to the opposite side of the lumber to provide dimensional stability and improved aesthetic properties (see step 5).

The following example is presented as illustrative of the present invention and should not be considered to be in limitation thereof.

EXAMPLE A common grade lumber piece having an actual thickness of 1 /2 inches and a width of 5 /2 inches, i.e., lumber designated in the trade as 2 X 6, was cut along a plane equi-distant between its faces using a saw that removed a V8 inch kerf. The two 1 H16 inch pieces thus produced were each planed to a thickness of /8 inch and a /8 inch thick piece of smooth surfaced hardboard was laminated to one surface of each piece with waterbase contact adhesive. Cracks and knot holes were filled with putty and sanded. 60 pound density Kraft paper was then glued to the surface of the lumber piece opposite the hardboard. The resultant products were found to possess excellent utility in the construction of cornices.

One skilled in the art will be aware of the fact that for widths greater than 8 inches, the standard for finish lumber is A inch less than the standard for common lumber and will realize that products greater than 8 inches should be edge trimmed A inch by conventional means to conform to the finish standard width.

While the dimensions and sizes set forth herein form a part of the invention, it is to be understood that such dimensions and sizes are approximate, and that minor variations inherent in machine inaccuracies and minor variations achieving essentially the same result are contemplated.

It will be readily apparent to one skilled in the art that many modifications and variations of the present invention may be made without departing from the spirit and scope thereof. Also, while the invention has been described as particularly applicable to the construction industry, it will be apparent that lumber produced in accordance with the present invention will be useful for other purposes, such as in the manufacture of furniture.

What is claimed is:

l. A process for preparing improved lumber products from common grade lumber to meet the requirements of clear grade lumber which comprises cutting a common grade lumber piece having a-thickness of about 1% inches along a plane substantially equi-distant be-. tween its two faces to form two lumber pieces, planing each of said two lumber pieces to a thickness of inch and adhesively laminating A: inch hardboard to the face of each of said pieces to form lumber products having a thickness of substantially /1 inch.

2. The process of claim 1, wherein a backing sheet is adhesively laminated to the surface of said piece opposite the surface upon which the hardboard is laminated. 3. The process of claim 1, wherein said hardboard is adhesively laminated to said piece with a water-base contact adhesive.

4. A process for preparing improved lumber products from common grade lumber to meet the requirements of clear grade lumber comprising a. providing a common gradelumber having a thickness of 1% inches;

b. removing a A; inch section from said lumber along a plane equi-distant between its faces to produce two pieces having a thickness of 1 1/16 inch;

c. planing the surface of each piece exposed by cutting to a depth of 1/16 inch to produce a piece having a thickness of inch; and

d. adhesively laminating Vs inch hardboard to one surface of each piece to produce a product having a thickness of inch. 

1. A PROCESS FOR PREPARING IMPROVED LUMBER PRODUCTS FROM COMMON GRADE LUMBER TO MEET THE REQUIREMENTS OF CLEAR GRADE LUMBER WHICH COMPRISES CUTTING A COMMON GRADE LUMBER PIECE HAVING A THICKNESS OF ABOUT 11/2 INCHES ALONG A PLANE SUBSTANTIALLY EQUI-DISTANT BETWEEN ITS TWO FACES TO FORM TWO LUMBER PIECES, PLANNING EACH OF SAID TWO LUMBER PIECES TO A THICKNESS OF 5/8 INCH AND ADHESIVELY LAMINATING 1/8 INCH HARDBOARD TO THE FACE OF EACH OF SAID PIECES TO FORM LUMBER PRODUCTS HAVING A THICKNESS OF SUBSTANTIALLY 3/4 INCH.
 2. The process of claim 1, wherein a backing sheet is adhesively laminated to the surface of said piece opposite the surface upon which the hardboard is laminated.
 3. The process of claim 1, wherein said hardboard is adhesively laminated to said piece with a water-base contact adhesive.
 4. A process for preparing improved lumber products from common grade lumber to meet the requirements of clear grade lumber comprising a. providing a common grade lumber having a thickness of 1 1/2 inches; b. removing a 1/8 inch section from said lumber along a plane equi-distant between its faces to produce two pieces having a thickness of 11/16 inch; c. planing the surface of each piece exposed by cutting to a depth of 1/16 inch to produce a piece having a thickness of 5/8 inch; and d. adhesively laminating 1/8 inch hardboard to one surface of each piece to produce a product having a thickness of 3/4 inch. 